Thermally crosslinked sulfonated polybenzimidazole membranes and their performance in high temperature polymer electrolyte fuel cells

Title
Thermally crosslinked sulfonated polybenzimidazole membranes and their performance in high temperature polymer electrolyte fuel cells
Authors
김형준장종현헨켄스마이어디억박현서아나스타시아N. Nambi KrishnanDavid AiliQingfeng Li
Keywords
High temperature polymer electrolyte fuel cell; Sulfonated polybenzimidazole; Thermal crosslinking; Stability; High current density
Issue Date
2019-10
Publisher
Journal of membrane science
Citation
VOL 588-8
Abstract
The degradation pathway of phosphoric acid doped polybenzimidazole membranes in high temperature polymer electrolyte membrane fuel cells depends on the acid contents. If it is high, creep is discussed as the main reason. If it is low (membranes prepared by solvent evaporation and post-doping), the main cause may be loss of acid due to evaporation. The net transport of acid to the anode side at high current densities should also lead to local softening of the membrane, which could be mitigated by crosslinking the membrane. Here we show that sulfonated para-polybenzimidazole membranes can be stabilized by curing at 350  °C. In contrast to meta-polybenzimidazole and sulfonated para-polybenzimidazole, crosslinked sulfonated para-polybenzimidazole is insoluble in dimethylacetamide at room temperature and phosphoric acid at 160  °C. At 160  °C and 5% relative humidity the conductivity of crosslinked sulfonated para-polybenzimidazole and meta-polybenzimidazole is 214  mS  cm− 1 and 147  1, respectively. At 600  mA cm− 2, the voltage decay rate is 16  μV h− 1, much lower than published for commercial meta-polybenzimidazole (308  1). Furthermore, the average voltage at 600  2 is 523  mV, while a previously published cured meta-polybenzimidazole membrane only reaches 475  mV.
URI
http://pubs.kist.re.kr/handle/201004/69570
ISSN
0376-7388
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KIST Publication > Article
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